摘要:

SUMMARYFord, J. 1974. Concepts of subspecies and hybrid zones, and their applications in Australian ornithology. Emu 74; 113–123.Taxonomic, evolutionary and biological concepts of the subspecies are discussed. Criticisms of taxonomic and evolutionary concepts are briefly reviewed. Some aspects of the subspecies in relation to the biological species concept and hybrid zones are discussed. Currently there are two schools of opinion in Australian ornithology: a traditional school using a purely taxonomic concept and another embracing a concept having both taxonomic and evolutionary connotations. It is concluded that the emphasis should be placed on the study of geographical variation and the determination of zones of secondary hybridization rather than on the application of a trinomial to every distinguishable population.

ISSN:0158-4197    

DOI:10.1071/MU974113

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

SUMMARYAbbott, I. 1974. The avifauna of Kangaroo Island and causes of its impoverishment. Emu 74: 124–134.Kangaroo Island has 50 per cent of the species of landbirds that breed on Fleurieu Peninsula, 14 km distant, and about 80 per cent of the species on Yorke or Eyre Peninsulas. Though often visited by ornithologists during the last 67 years. 55 species of landbirds known on the mainland have never been recorded. 33 others have teen recorded less than five times. The marked avifaunal impoverishment of the island is probably not because of differences in habitat OT vegetation, but because these 88 Species have immigrated very seldom to the island.The pattern of distribution of 226 species of landbirds over southern Australia, including Tasmania and the islands in Bass Strait, suggests that nearly 25 per cent of these arrived postglacially in coastal South Australia. Probably only 25 of the 90 species absent from Kangaroo Island were there in the past but have became extinct. Sixteen of these occur in Tasmania but not on any Bass Strait islands, and are presumably extinct there also. One native species has established itself on Kangaroo Island in the last 67 years.The theoretical expectation that island populations should have more variable bills or tarsi than mainland populations was confirmed respectively for maleAcanthiza pusillaand femalePhylidonyris pyrrhoptera.

ISSN:0158-4197    

DOI:10.1071/MU974124

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

SUMMARYCounsilman, J. J. 1974. Waking and roasting behaviour of the Indian Myna, Emu 74; 135–148.Waking and roosting ofAcridotheres tristisat communal roosts were studied during two years in Auckland. Mynas sleep communally in trees all the year, the only exceptions being incubating and brooding females. Birds use some roosts during late spring and summer only and some roosts throughout the year. The temporary roosts are formed just before reproduction and, when they are formed, numbers of birds visiting year-round roosts drop sharply; they are gradually deserted during the summer long before the end of breeding. At year-round roosts the times of assembly and of departure show trends relative to civil twilight and are latest and earliest respectively when breeding is at a peak. The intensities of light at which birds arrive and depart are the lowest at this time. These trends are probably because reproductive hormones affect the birds' sensitivity to physical cues or cause an increased attraction to the territory and nest. Throughout the breeding season changes in the status of arriving birds (singles, pairs and groups) correlate with the changing numbers of breeding pairs.Light is probably the only physical factor that could provideconsistentcues to times of waking and roosting. Other factors, such as temperature and humidity, may have an effect, especially on the periods of assembly and departure. An endogenous clock, set by light and possibly a socialZeitgeber, allows early departures, especially important to breeding individuals; it prevents a waste of time and energy during the day that might come from premature roosting.The time available to breeding birds for feeding and for collecting food for nestlings is increased by leaving early from, and arriving late at, roosts. An early defence of the territory may also advance the time of departure, Vocalizations at roosts do not advertise them but are more proximate socially, as when these calls are given during the day. Gatherings before roosting provide protection from predation, which may be greater in evening, but do not always prevent foraging. Communal steeping protects Mynas more from predators than if they slept solitarily. Other advantages, such as maintaining the unity of juvenile flocks and an increased efficiency in finding food, come from sleeping communally, but at any one time most birds in Auckland do not exploit these additional benefits.

ISSN:0158-4197    

DOI:10.1071/MU974135

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

SUMMARYMarchant, S. 1974. Analysis of nest-records of the Willie Wagtail. Emu 74: 149–160.Five hundred and sixty-five nest-record cards of the Willie Wagtail are analysed. Information on habitat of the species is biased by the distribution and habits of observers, but there is little suggestion that the bird usually lives near water. The nest is well known. Adults may dismantle nests for building later ones, Nests are found from below one to higher than fifteen metres, average almost exactly 3 m. but the distribution could be bimodal, below six and above seven metres, which would be caused by the structure of the native vegetation. Eggs are laid at an interval of 24 hours, usually between 05:00 and 09:00. The clutch is two to four eggs, average 3.1, but the sample is too small and scattered for significant annual or latitudinal differences to appear. Significantly smaller clutches are laid below 500 m than above and differences are significant between coastal, hilly and inland areas. The incubation and nestling periods are each fourteen days as a rule. Total breeding success is 58 per cent, apparently higher (63%) in late broods after 30 November than in earlier (56%); C/3 is most successful in producing flying young (60%); but differences in success are not significant statistically. Pallid Cuckoos occasionally parasitize nests, usually unsuccessfully, presumably because there is no mimicry of eggs. The breeding season is from mid-August to late January, but mostly in October, November and December, which roughly correspond to the times of first, second and third broods respectively. Differences in timing between different areas cannot be detected because of the scattered small sample, but laying probably starts two weeks earlier as a rule at Eudunda, SA, than in ACT. The same nest is often used for two or three broods.There are obvious difficulties in analysing data from cards from a very large area throughout which the climate is not the same each year. Climatic effects mask those of latitude, or latitudinal effects those of altitude. Concentrated data from a few widely separated places would be easier to compare and analyse.

ISSN:0158-4197    

DOI:10.1071/MU974149

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

SUMMARYFord, J. 1974. Speciation in Australian birds adapted to arid habitats. Emu 74: 161–168.Several stages of speciation can now be identified in some birds occurring mainly in the mulga habitat of the arid parts of Australia. Speciation in birds adapted to the stony andTriodia-sandhill deserts has occurred more commonly than previously suspected. Only sedentary birds of the mulga and desert habitats have produced differentiated isolates. The Eyrean Barrier has played an important role in the production of species adapted to arid conditions from those adapted to mesic conditions and in the speciation of inhabitants of the mulga. Some isolates of desert species may have been formed during pluvial periods in the Pleistocene.

ISSN:0158-4197    

DOI:10.1071/MU974161

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

SUMMARYWilson, M. 1974. Birds of the Simpson Desert. Emu 74: 169–176.Two Crossings of the Simpson Desert Were Made in April and July-August 1969. Notes on 83 species of birds seen during these crossings are given. These are supplemented by notes by S. A. Parker and by personnel of the CSIRO-NTA Dingo Survey.

ISSN:0158-4197    

DOI:10.1071/MU974169

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

SUMMARYFord, J., and S. A. Parker. 1974. Distribution and taxonomy of some birds from south-western Queensland. Emu 74: 177–194.In December 1971 and January 1972 an expedition was made to south-western Queensland. From observations made and specimens collected the distribution of some species can now be better defined. The taxonomy ofBarnardius zonarius, Pomtostomus superciliosus, Pomatostomus halli, Eremiornis carteri, Amytornis striatus, Stipiturus ruficepsandColluricincla harmonicais discussed.

ISSN:0158-4197    

DOI:10.1071/MU974177

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU974195a

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU974195b

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU974195c

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor